Experimentally supported control design for a direct drive robot

Discrete-time sliding mode control of a direct-drive robot manipulator

“…Practical procedures to identify an FRF as shown in Fig. 3 are explained in [15,16]. Note that the given FRF represents the dynamics of joint 1, as it was obtained by averaging the dynamics identified for different robot postures [16].…”

“…2, is an experimental facility for research in motion control [13][14][15][16]. Closed-form models of the robot kinematics and rigidbody dynamics are available in [14].…”

“…3, it can be noticed that the rigid-body dynamics dominate up to approximately 20 Hz. Due to insuf- between u 1 and the observed output y 1 from (10) [15]. The output is corrupted with quantization noise η 1 from the incremental encoder.…”

“…The proportional and derivative gains (see (15)). If we apply (21) to (9), and take (20) into account, we obtain: β .…”

“…For β 1 ≤12, the relative damping is unreasonably high, and may excite flexible dynamics and amplify quantization noise. An appropriate set of PD gains, away from the "stability" boundary β 1 =12, can be found using loop-shaping, as explained in [15][16][17] ). Experiments showed no need for higher ρ i .…”