JEMRMS operational performance verification approach
- Paper ID
90-iaf-077
- author
- company
National Space Development Agency of Japan
- country
Japan
- year
1990
- abstract
In paper, we will discuss the operational aspect of the JEMRMS(Japanese Experiment Module Remote Manipulator System) and how to verify it’s mission feasibility practically. Newly installed test bed was used for demonstrating- the performance verification of the 10 meter long Main Arm (3-DOF 2-dimensional model) and 2 meter Small Fine Arm (6-DOF 3-dimensional) with common hand controller and control algorism. Also tested were operability of the Small Fine Arm with payload sustained under near zero gravity condition and maneuverability for the expected dexterous mission requirements like ORU (Orbital Replacement Unit)change out or antenna assembling. The Main Arm transports mission payloads by preprogrammed control mode, but payload berthing/ retrieving will be done by manual control mode. Two dimensional model of the Main Arm which consists of three pitch joints(shoulder,elbow and wrist)and booms were installed on the test bed (10 x 5 m flat floor ) via air bearings so that friction free movement over the floor is realized. Control accuracies are evaluated for both preprogrammed and manual control modes. It was observed that Main Arm control through the TV screen image only was difficult for large transit movement of the arm by the operator, so that preprogrammed operation is effective. For payload positioning, the arm basement (shoulder oriented) coordinate system is preferable for coarse positioning, and tip (wrist or payload) oriented coordinate system is preferable for fine positioning. At the same time, the arm position detection algorism using the TV screen image of the target placed on the payload was evaluated. This method will improve the arm positioning capability. The six degrees of freedom functional model of the Small Fine Arm was constructed and it’s operation was demonstrated under the various operational conditions. The slave arm was installed on the test bed and controlled with gravity compensation by software. The payload weight was compensated by the test rig. Typical mission operational tasks were evaluated with force feedback control mode. The hand controller is an orthogonal type 6-DOF master arm and commonly used for Main Arm and Small Fine Arm manipulation. The combination of the rate control mode and position control mode was effective for the dexterous manipulator operations. Test results obtained and evaluation will be of great use for the hardware design and on orbit operation planning activities.