Control concepts Traditional PI or PID controllers often addition- ally use a feed forward that is proportional to speed and acceleration in order to compen- sate for friction and inertia. More sophisticated control concepts may also be used on a case-by-case basis. These include − Observer-supported control − Sensorless control through evaluation of motor parameters (EMF, impedance) − Dual loop control for load-side control with compensation of backlash and elasticity − Gain scheduling One key aspect for users is automatic control- ler tuning, which is available as standard for all maxon motor control products and ensures optimum system adjustment.
Multi-axis motion controllers Multi-axis motion controllers are freely pro- grammable controllers that make it possible to easily synchronize coordinated movements of several axes. Powerful commands are pro- vided, for example for completing the following tasks (among others) − PLC functionality as a sequential program (cyclical processing) or as state machines that work in parallel − Coordinated time or path-synchronous multi-axis positioning − Synchronous execution of CAM profiles (cam disks) on several axes − Control of freely definable path trajectories with different kinematics (X-Y tables, 3D plotters, Scara robots, Delta robots…) − Master-slave synchronization of several axes with marker comparison.
DC tacho control The motor must be equipped with a DC tacho-meter that provides a speed propor- tional signal. In the maxon modular system, the tachometer rotor is mounted directly on the through motor shaft, resulting in a high resonant frequency. − Limited service life of the DC tacho generator The motor is provided with a voltage that is proportional to the applied speed set value. The speed would drop with increasing motor load. The compensation circuitry increases the output voltage with increasing motor current. The compensation must be adjusted to the ter- minal resistance of the motor which depends on temperature and load. − For speed control only − Analog feedback signal IxR compensation The attainable speed precision of such a sys- tem is subject to limits in the percent range. − Favorably priced and space-saving − No tacho-generator or encoder required − Only analog speed control possible − Less precise control when there is a load change − Ideal for low-cost applications without high demands on speed accuracy
Principle: Multi-axis motion controllers
Multi-axis motion controllers
PC or SPS
position encoder signal
Technology – short and to the point
September 2020 edition / subject to change
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