Abstract:
A system for controlling a tension of a tether between an object and a load tethered to the object comprises magnetorheological (MR) fluid actuator unit(s) including at least one torque source and at least one MR fluid clutch apparatus coupled to the at least one torque source to receive torque from the at least one torque source, the MR fluid clutch apparatus controllable to transmit a variable amount of torque via an output of the MR fluid actuator unit. A tensioning member is connected to the output so as to be pulled by the output member upon actuation of the magnetorheological fluid clutch apparatus, a free end of the tensioning member adapted to exert a pulling action when being pulled by the output member. Sensor(s) provide information indicative of a relation between the object and the load tethered to the object. A controller controls the at least one MR fluid clutch apparatus in exerting the pulling action based on said information.
Abstract:
A control system is provided for controlling movements of an end effector connected to a clutch output of at least one magnetorheological (MR) fluid clutch apparatus. A clutch driver is configured to drive the at least one MR fluid clutch apparatus between a controlled slippage mode, in which slippage between a clutch input and the clutch output of the MR fluid clutch apparatus varies, and a lock mode, in which said slippage between the clutch input and the clutch output is maintained below a given threshold, the clutch output transmitting movement to the end effector. A motor driver is configured to control a motor output of at least one motor, the motor output coupled to the clutch input. A mode selector module is configured to receive signals representative of at least one movement parameter of the end effector, the mode selector module selecting a mode between the controlled slippage mode and the lock mode of the clutch driver based on the signals, and switching the selected mode based on the signals. A movement controller controls the clutch driver and the motor driver to displace the end effector based on at least one of the selected mode and on commanded movements of the end effector for the end effector to achieve the commanded movements. A method for controlling movements of an end effector connected to the MR fluid clutch apparatus is also provided.