초록 ▼

An actuator and movement linkage system for moving a load, such as a control surface of aircraft, in relation to a carrying structure includes an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor syste

An actuator and movement linkage system for moving a load, such as a control surface of aircraft, in relation to a carrying structure includes an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor system to be driven thereby, and transfer units provided for mechanically connecting the actuator device to move the load. Fault tolerant and release devices are provided both in the electrical motor system and in the actuator device to make the actuator and movement linkage system fault tolerant to at least single faults in the actuator and movement linkage system,

대표청구항 ▼

What is claimed is: 1. An actuator and movement linkage system for moving a load in relation to a carrying structure, including an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor system to be driven

What is claimed is: 1. An actuator and movement linkage system for moving a load in relation to a carrying structure, including an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor system to be driven thereby, transfer units provided for mechanically connecting the actuator device to move the load, fault tolerant and release devices both in the electrical motor system and the actuator device and arranged to make the actuator and movement linkage system fault tolerant to at least single faults in other parts of the actuator and movement linkage system, wherein the electrical motor system includes an electric motor having stator windings, power switches for supplying current to the motor windings, power control units, a rail voltage system including voltage rails, rail voltage capacitors connected between the voltage rails, motor control processors, the fault tolerant and release devices include that at least two power sources and a connecting device are provided for connecting all of the power control units to an operational power source selected among said at least two power sources for making the actuator and movement linkage system tolerant against a power source fault, that the rail voltage capacitors include a plurality of capacitors connected in series with each other, the capacitors in said plurality of capacitors rated to withstand the voltage appearing if one of the capacitors is short-circuited for making the actuator and movement linkage system tolerant against short circuit failures in the rail voltage capacitors, that at least six motor stator windings or winding groups without any direct metallic contact between the windings or winding groups are arranged for making the actuator and movement linkage system tolerant against motor winding failures and against power switch failures, that the power switches are arranged in a plurality of power switch units connected to respective ones of the motor windings for controlling the amount of electrical current passing through the motor windings, and hence the torque delivered by or derived from said respective windings, for making the actuator and movement linkage system tolerant against loss of generated torque by failures in the power switches, extra switches that in case of short-circuit in the power switches or in the rail voltage system are arranged to break the current loop that otherwise would have been created by one of the motor windings, power switch unit diodes and a short-circuited device, and that the power switches are arranged in a plurality of power switch units connected to respective ones of the motor windings for controlling the amount of electrical current passing through the respective motor windings, and hence the torque delivered by or derived from said respective motor windings, for making the actuator and movement linkage system tolerant against unintended braking torque caused by short-circuits in the power switches or short-circuits over the rail voltage system, that a plurality of motor control processors and devices to force all power control units to accept commands from one and the same, not faulty, motor control processor are arranged for making the actuator and movement linkage system tolerant against faults in motor control processors and for eliminating possible conflicts between the motor control processors, and removable release devices joining or locking the transfer units and arranged to be removed in the case of a fault, allowing the transfers unit to move at least to some extent freely in relation to each other for making the actuator and movement linkage system tolerant against jamming in moving mechanical parts of the actuator device. 2. An actuator and movement linkage system for moving a load in relation to a carrying structure, including an electric motor system, an actuator device connectable or connected to the load to move the load, the actuator device connected to the electric motor system to be driven thereby, fault tolerant and release devices both in the electrical motor system and the actuator device and arranged to make the actuator and movement linkage system fault tolerant to at least single faults in other parts of the actuator and movement linkage system. 3. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, that the electric motor system still is capable of driving the actuator device. 4. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, that the electric motor system still is capable of driving the actuator device. 5. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include mechanical release device connected between the actuator device and the load, the mechanical release device arranged to allow, in the case of a fault in a component of the electric motor system or in the actuator device, the actuator device to move freely. 6. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes power control units and the fault tolerant and release devices include that at least two power sources and a connecting device are provided for connecting all of the power control units to an operational power source selected among said at least two power sources for making the actuator and movement linkage system tolerant against a power source fault. 7. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes voltage rails and rail voltage capacitors connected between the voltage rails and the fault tolerant and release devices include that the rail voltage capacitors include a plurality of capacitors connected in series with each other, the capacitors in said plurality of capacitors rated to withstand the voltage appearing if one of the capacitors is short-circuited for making the actuator and movement linkage system tolerant against short circuit failures in rail voltage capacitors. 8. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes an electric motor having stator winding and the fault tolerant and release devices include that at least six motor stator windings or winding groups without any direct metallic contact between the windings or winding groups are arranged for making the actuator and movement linkage system tolerant against motor winding failures. 9. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes motor windings and stator current switches for supplying current to the motor windings and the fault tolerant and release devices include that at least six motor stator windings or winding groups without any direct metallic contact between the windings or winding groups are arranged for making the actuator and movement linkage system tolerant against power switch failures. 10. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes motor windings and power switches and the fault tolerant and release devices include that the power switches are arranged in a plurality of power switch units connected to respective ones of the motor windings for controlling the amount of electrical current passing through the motor windings, and hence the torque delivered by or derived from said respective windings, for making the actuator and movement linkage system tolerant against loss of generated torque by failures in the power switches. 11. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes motor windings, power switches and a rail voltage system and the fault tolerant and release devices include extra switches that in case of a short-circuit in the power switches or in the rail voltage system are arranged to break the current loop that otherwise would have been created by one of the motor windings, power switch unit diodes, and a short-circuited device, and that the power switches are arranged in a plurality of power switch units connected to respective ones of the motor windings for controlling the amount of electrical current passing through the respective motor windings, and hence the torque delivered by or derived from said respective windings, for making the actuator and movement linkage system tolerant against unintended braking torque caused by short-circuits in the power switches or short-circuits over the rail voltage system. 12. The actuator and movement linkage system of claim 2, wherein the electrical motor system includes motor control processors and power control units and the fault tolerant and release devices include that a plurality of motor control processors and devices to force all power control units to accept commands from one and the same, not faulty, motor control processor are arranged for making the actuator and movement linkage system tolerant against faults in motor control processors. 13. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include that a plurality of motor control processors and devices to force all power control units to accept commands from one and the same, not faulty, motor control processor for eliminating possible conflicts between the motor control processors. 14. The actuator and movement linkage system of claim 2, wherein transfers units are provided for mechanically connecting the actuator device to move the load, and the fault tolerant and release devices include removable release devices joining or locking the transfer units and arranged to be removed in the case of a fault, allowing the transfers unit to move at least to some extent freely in relation to each other for making the actuator and movement linkage system tolerant against jamming in moving mechanical parts of the actuator device. 15. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device to move freely. 16. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device not to influence the movement of the load. 17. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device not to prevent the movement of the load. 18. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device not to obstruct the movement of the load. 19. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device not to delay the movement of the load. 20. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the electric motor system to permit the actuator device not to retard the movement of the load. 21. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, that the electric motor system allows the actuator device not to make the movement of the load significantly more difficult than before the occurrence of the fault. 22. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the actuator device to move freely. 23. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices are arranged to allow, in the case of a fault in a component of the actuator and movement linkage system, the actuator device not to significantly influence the movement of the load. 24. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, that the electric motor system allows the actuator device to move freely. 25. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, the electric motor system to permit the actuator device not to influence the movement of the load. 26. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, the electric motor system to permit the actuator device not to prevent the movement of the load. 27. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, the electric motor system to permit the actuator device not to obstruct the movement of the load. 28. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, the electric motor system to permit the actuator device not to delay the movement of the load. 29. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, the electric motor system to permit the actuator device not to retard the movement of the load. 30. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include electrical fault tolerant and release devices included in the electric motor system, the electrical fault tolerant and release devices connected to or in other electric components in the electric motor system and arranged to allow, in the case of a fault in a component of the electric motor system, that the electric motor system allows the actuator device not to make the movement of the load significantly more difficult than before the occurrence of the fault. 31. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include a mechanical release device connected between the actuator device and the load of the actuator device, the mechanical release device arranged to allow, in the case of a fault in a component of the electric motor system or in the actuator device, that the actuator does not to significantly influence the movement of the load. 32. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include a mechanical release device connected in an output unit of the actuator device, the mechanical release device arranged to allow, in the case of a fault in a component of the electric motor system or in the actuator device, the actuator device to move freely. 33. The actuator and movement linkage system of claim 2, wherein the fault tolerant and release devices include a mechanical release device connected in an output unit of the actuator device, the mechanical release device arranged to allow, in the case of a fault in a component of the electric motor system or in the actuator device, that the actuator does not to significantly influence the movement of the load. 34. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having at least one stator, each of said at least one stator having at least one rotor coupled to a mechanical load for driving the mechanical load, coils or windings of a plurality of electrical motor phases, the coils or windings assembled in said at least one stator, a plurality of motor control processors for issuing commands and receiving data, a plurality of power control units for controlling electric current in the coils or windings of the plurality of electrical motor phases, each of the power control units connected to the coils or windings of an individual subset of the electrical motor phases for driving currents in said coils or windings, each of the power control units arranged to be connectable to anyone of the motor control processors to receive commands from and provide data, to the motor control processors, a switch or switching means for forcing all of the power control units to be all, jointly or commonly, controlled by any single one of the motor control processors, and a failure detector for identifying failure of one of the motor control processors and, in the case where a failure is identified, for forcing all of the power control units to be controlled by another of the motor control processors. 35. The fault tolerant electric motor system of claim 34, wherein each of the power control units includes: a power switch unit including power switches, the power switch unit connected to the coils or windings of said individual subset of the electrical motor phases, the power switches being rendered on and off in response to commands from that one of motor control processors that controls the power switch units, for controlling the amount of electrical current passing through said coils or windings, and hence the torque delivered by or derived from said coils or windings. 36. The fault tolerant electric motor system of claim 35, wherein each of power control units has the power switches of its power switch unit connected as at least one H-bridge for each of the electrical motors phases included in said individual subset of the electrical motor phases. 37. The fault tolerant electric motor system of claim 36, wherein each of the at least one H-bridge includes four power switches. 38. The fault tolerant electric motor system of claim 34, wherein the at least one electrical motor has an output device connectable to an actuator. 39. The fault tolerant electric motor system of claim 34, wherein the coils or windings of all of the electrical motor phases are assembled in one stator. 40. The fault tolerant electric motor system of claim 34, wherein for each of the motor control processors individual detectors are connected in the path of electrical power or electrical current to the coils or windings of the electrical motor phases. 41. The fault tolerant electric motor system of claim 40, wherein the individual detectors for one of the motor control processors are separate or insulated from the individual detectors for another one of the motor control processors. 42. The fault tolerant electric motor system of claim 34, wherein the plurality of motor control processors are arranged to issue motor current switches on-time commands. 43. The fault tolerant electric motor system of claim 34, wherein the plurality of motor control processors are arranged to receive sensed values of parameters. 44. The fault tolerant electric motor system of claim 34, wherein each of the power control units is arranged to provide sensed values of parameters to the motor control processors. 45. The fault tolerant electric motor system of claim 34, wherein each of the power control units includes: a power switch unit including power switches, the power switch unit connected to the coils or windings of said individual subset of the electrical motor phases, the power switches being rendered on and off in response to commands from that one of motor control processors that controls the power switch units, for controlling the amount of electrical current passing through said coils or windings to make the torque delivered by or derived from said coils or windings being regulated by the on-time of the power switches. 46. The fault tolerant electric motor system of claim 34, wherein the at least one electrical motor has an output shaft connectable to an actuator. 47. The fault tolerant electric motor system of claim 34, wherein for each of the motor control processors individual detectors are connected in each of the power control units and hence in the path of electrical power or electrical current to the coils or windings of the electrical motor phases. 48. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having coils or windings of a plurality of electrical motor phases, a plurality of power control units for controlling electric current in the coils or windings of the plurality of electrical motor phases, each of the power control units connected to the coils or windings of an individual subset of the electrical motor phases for driving currents in said coils or windings and each of the power control units arranged to receive, for controlled supply to the coils or windings, electrical power or electrical current from anyone of a plurality of electrical power sources or electrical current sources, a first switch unit for forcing each of the power control units to normally or in a first basic state take electrical power or electrical current from an assigned or preferred one of the electrical power sources or electrical current sources, and a second switch unit for forcing each of the power control units to take electrical power or electrical current from a non-preferred one of the electrical power sources or electrical current sources in a second exceptional case or in the case where the assigned or preferred one of the electrical power sources or electrical current sources fails. 49. The fault tolerant electric motor system of claim 48, in which the said first switch unit is a set of diodes which will insulate a failing preferential power source from the power control unit in case a non-preferential electrical power source or electrical current source is connected by said second switch unit and provides the power control unit with a higher voltage than what is provided by the preferential electrical power source or electrical current source. 50. The fault tolerant electric motor system of claim 48, in which the said first switch unit and the said second switch unit both are sets of diodes which will reduce or eliminate the current taken from a lower voltage power source to the power control unit and increase the current taken from a higher voltage power source to the power control unit. 51. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having coils or windings of a plurality of electrical motor phases, terminals to receive electrical power or electrical current, a power switch unit including power switches, the power switch unit connected to the coils or windings of the electrical motor phases, and a capacitive DC power storage or decoupling unit to which the said power switch unit is connected, the capacitive DC power storage or decoupling unit including a plurality of serially connected groups of parallel connected capacitors, and the voltage rating of the capacitors permitting them to withstand the total voltage of the capacitive DC power storage or decoupling unit even if one of the said group of parallel connected capacitors is short-circuited. 52. The fault tolerant electric motor system of claim 51, further including voltage detectors connected to measure the voltage over the whole capacitive DC power storage or decoupling unit and the voltage over a subset of the serially connected groups of parallel connected capacitors. 53. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having coils or windings of a plurality of electrical motor phases, terminals to receive AC electrical power or electrical current, a rectifier unit to convert received AC electrical power or electrical current to DC electrical power or electrical current, and an averaging unit coupled to the rectifier unit for receiving the converted DC electrical power or electrical current for averaging or smoothing it, the averaging unit including a plurality of serially connected groups of parallel connected capacitors the voltage rating of the capacitors permitting them to withstand the total voltage of the averaging unit even if one of the said group of parallel connected capacitors is short-circuited. 54. The fault tolerant electric motor system of claim 53, further including voltage detectors connected to measure the voltage over the whole averaging unit and the voltage over a subset of the serially connected groups of parallel connected capacitors. 55. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having coils or windings of a plurality of electrical motor phases, terminals to receive electrical power or electrical current, a power switch unit including power switches, the power switch unit connected to the coils or windings of the electrical motor phases, and a capacitive DC power storage or decoupling unit to which the said power switch unit is connected, the capacitive DC power storage or decoupling unit including a plurality of in parallel connected groups of serially connected capacitors, and the voltage rating of the capacitors permitting them to withstand the total voltage of the capacitive DC power storage or decoupling unit even if one of the said group of parallel connected capacitors is short-circuited. 56. A fault tolerant electric motor system for driving a mechanical load including: at least one electric motor having coils or windings of a plurality of electrical motor phases, power switch units connected to respective ones of the coils or windings for controlling the amount of electrical current passing through the coils or windings of the respective one of the electrical motor phases, and hence the torque delivered by or derived from said respective coils or windings, at least one switch connected in series with coils or windings of each of the electrical motor phases, the at least one switch element arranged to always be in a conducting or closed state during faultless operation of that one of the power switch units controlling the electrical current for the coils or windings of that one of the electrical motor phases to which the at least one switch element is connected, and setting means for setting the at least one switch element in an insulating or open state if one of the switches in that one of the power switch unit that is connected to that one of the electrical motor phases to which the at least one switch element is connected enters a permanent on-state or a permanent conducting or closed state. 57. The fault tolerant electric motor system of claim 56, wherein the at least one switch element includes a current sensitive fuse, and the setting means for setting the at least one switch element is an electrical current having a sufficient intensity and caused by the length of the on-time of one of power switches included in said that one of the power switch units. 58. The fault tolerant electric motor system of claim 56, wherein the at least one switch element includes an electrical relay, and the setting means for setting the at least one switch element is an electrical current through a coil of the relay. 59. The fault tolerant electric motor system of claim 56, wherein the at least one switch element includes a temperature sensitive fuse in thermal contact with at least one of the coils or windings of said that one of the electrical motor phases, and the setting means for setting the at least one switch element is an electrical current having a sufficient intensity and caused by the length of the on-time of one of power switches included in said that one of the power switch units. 60. The fault tolerant electric motor system of claim 56, wherein the at least one switch element includes a temperature sensitive fuse in close thermal contact with heating means; the setting means for setting the at least one switch element is an electrical current causing the heating means to increase the temperature of the temperature sensitive fuse to surpass the trip temperature of the temperature sensitive fuse. 61. The fault tolerant electric motor system of claim 56, wherein the power switch units are arranged to control the amount of electrical current passing through the coils or windings of the respective one of the electrical motor phases to regulate the torque delivered by or derived from said respective coils or windings by the on-time of power switches included in the power switch units. 62. A fault tolerant actuator system including: a primary actuator, the length of which can be changed by a control signal and which is connectable to a load, a plurality of transfer units to transform the change of the length of the primary actuator to desired movements of the load, at least one removable element joining two of the transfer units, the at least one removable element arranged to force said two of the transfer units to move synchronously when the primary actuator is operational, and a release device arranged to move the at least one removable element from a first position forcing said two of the transfer units to move synchronously to a second position not forcing said two of the transfer units to move synchronously. 63. The fault tolerant actuator system of claim 62, wherein the release device includes an electric motor and a mechanical transmission for moving the release device. 64. The fault tolerant actuator system of claim 62, wherein the release device includes a pyrotechnic or explosive charge. 65. The fault tolerant actuator system of claim 64, further including a stopper or catch-up device, for stopping the movement of the removable device in such a way that the removable device will not damage parts of the fault tolerant actuator system and in such a way that the removable device, after being moved by the pyrotechnic or explosive charge will stay sufficiently far away from its initial position to no longer force said two of the transfer units to move synchronously. 66. The fault tolerant actuator system of claim 64, further including a stopper or catch-up device for stopping the movement of the removable device in such a way that the removable device will not damage parts of the load and in such a way that the removable device, after being moved by the pyrotechnic or explosive charge will stay sufficiently far away from its initial position to no longer force said two of the transfer units to move synchronously. 67. The fault tolerant actuator system of claim 65 or 66, wherein the stopper or catch-up device includes an air-cushion device. 68. The fault tolerant actuator system of claim 65 or 66, wherein the stopper or catch-up device includes a plastically deformable device. 69. The fault tolerant actuator system of claim 65 or 66, wherein the stopper or catch-up device is arranged to stop the movement of the removable device in such a way that the removable device will not damage parts of the fault tolerant actuator system or of the load. 70. The fault tolerant actuator system of claim 62, further including a device for ensuring that none of the primary actuator and said two of the transfer units, after a movement of the release device, will obstruct the load to move within its normal range of movements. 71. The fault tolerant actuator system of claim 62, wherein the release device includes an electric motor and a mechanical transmission including a gear box for moving the release device. 72. The fault tolerant actuator system of claim 62, wherein the release device includes and electric motor and a mechanical transmission including a reduction drive for moving the release device. 73. The fault tolerant actuator system of claim 62, wherein the release device includes an electric motor and a mechanical transmission including a belt drive for moving the release device. 74. The fault tolerant actuator system of claim 62, wherein the release device includes an electric motor and a mechanical transmission including a screw drive for moving the release device. 75. The fault tolerant actuator system of claim 62, wherein the release device includes an electric motor and a mechanical transmission including a rack and pinion device for moving the release device. 76. A fault tolerant actuator system for moving a load in relation to a carrying structure including: at least two transfer units mounted between the carrying structure and the load, at least one pair of removable devices for joining the at least two transfer units to each other and/or for locking the at least two transfer units to take a fixed position in relation to each other, and a pyrotechnical or explosive charge arranged to move, when ignited or detonated, the at least one pair of removable devices from the position joining the at least two transfer units or locking the at least two transfer units in a fixed position to another position not joining the at least two transfer units or locking the at least two transfer units to take a fixed position in relation to each other, the removable devices of said at least one pair moving, during the moving when the pyrotechnical or explosive charge is ignited or detonated, in a substantially symmetric way away from each other, this symmetric way of moving reducing reaction forces transferred from the pyrotechnical or explosive charge, when ignited or detonated, to the carrying system and to the load. 77. The fault tolerant actuator system of claim 76, wherein the removable devices of said at least one pair are arranged to move, during the moving by the pyrotechnical or explosive charge when ignited or detonated, in substantially opposite directions.