Mode Switching Control Research Articles

Paradigm for compliant motion control in environments with unknown or variable dynamics

Compliant control of robot manipulators in environments with unknown or variable dynamics is a broad area of research which has many unresolved problems. Due to the dynamic coupling between the robot and the environment in the constrained directions, hybrid control schemes seem best suited to perform the control since they can be tuned independently in each direction. The directional adaptive damping control scheme is an example of a hybrid control scheme that automatically determines the direction of the constraint and adapts the force response according to the surface stiffness. The extension of this scheme to the more general case where there are more than one constraint surfaces cannot be done easily because the estimation of the constraint's orientations is much harder in this case. Furthermore, if the constraints change abruptly, unwanted transients will be created because of the control mode switching. The use of reasoning with approximate or partial models of the environment appears to offer a solution to these problems.

The use of parallel logic in teaching engineering and science

The use of the analog computer in teaching engineering and science has become increasingly widespread. The reason for this vogue is that the analog computer can easily solve differential equations, linear and non-linear, which characterize so many physical systems. However when the mathematical model requires decision making logic switching, timing, memory or individual mode control of analog components, the need to add parallel logic to the analog computer becomes self-evident. This paper intends to show how it is possible to extend the capabilities of the analog computer by the addition of parallel logic.

A Fast Mode-Control Switch for Iterative Differential Analyzers

Operation of fast analog-hybrid computers at kilocycle iteration rates requires wideband amplifiers, low computing impedances, and electronic track-hold and integrator mode-control switching within tens of nanoseconds. This paper describes the design and circuit analysis of a new switched-amplifer mode-control circuit designed for the University of Arizona's ASTRAC II iterative differential analyzer. The bandwidth of the circuit in track is down 3 dB at 2.5 Mc, which accounts for a phase shift of 0.005 radian (≪ 0.3 deg) at 10 Kc. The circuits switch into COMPUTE (HOLD) in less than 80 ns; two or more integrators switch within 20 ns of each other. Voltage drift in the TRACK or RESET mode is within ±50 ?V/°C between ?20 to +60°C.