In 1948, Raymond C. Goertz designed what is considered to be the first successful bilateral (two-sided) teleoperation system to manipulate radioactive material from behind a leaded wall. Since then, teleoperation has advanced to completely remote systems with very high transparency, simulating a direct connection with the task environment to perform high-precision tasks such as surgery remotely. Avatars. The report aims to educate people about this increasingly adopted technology through video lectures, assignments, and a low-cost DIY kit: the focus of this paper.
Firstly, the quality of the DIY kit’s force measurement was to be improved, found to be affected most by physical disturbances, gravity and electromagnetic interference from the motor. Except for intense disturbances, satisfactory attenuation of undesired signals has been achieved with a Least-Mean-Square adaptive filter. This filter matches the noise measured by a ‘dummy’ load-cell (force sensor) to the noise in the ‘active’ load-cell’s measurement. To prevent distortion, basic noise estimation replaces this filter whenever significant force is applied to the handle.
Using this improved force measurement, two control architectures were to be implemented. While the 4-channel architecture was not completed, the position-measured force architecture significantly increased the transparency over the existing position-computed force architecture; when interacting with a rigid object and springs, the average force and position tracking errors were reduced by 61.7% and 31.6%, respectively. However, due to deviating and temperature-dependent motor constants, these percentages may vary between DIY kits.
Finally, the load-cells’ amplifiers were modified to increase their low sampling rate and thereby improve the system’s stability.