Control strategies for hardware-in-the-loop simulation of flexible space robots

Abstract

As a partner in the International Space Station (ISS), Canada is responsible for the verification of all tasks involving the special purpose dextrous manipulator (SPDM). Those verifications cannot be performed using software simulators only since the accuracy of existing contact dynamic models are yet to be confirmed, especially in the real-time mode required for verifying human operated processes. One option is to use a hardware-in-the-loop simulation (HLS), where the space hardware is simulated and the contact dynamics is emulated using a rigid robot performing the tasks. The main difficulty in this approach is the trade-off between the stability of the control loop and good performance. The control of the rigid robot in the HLS is investigated. Simplified linear systems are used to determine the limitations of the classical position-based control when contact occurs. A new control scheme in which the slave robot is driven in acceleration is proposed. Both methods were tested experimentally and the results show the benefit of using this new acceleration control approach.