RoboteQ AX2850 user manual Command Control Curves

General Operation

TABLE 6. Acceleration setting table

Acceleration	Acceleration
Setting Using	Setting Using	%Acceleration per	Time from 0 to
RS232	Switches	16ms	max speed
15 Hex	-	17.97%	0.089 second
05 Hex	5	18.75%	0.085 second

When configuring the acceleration parameter using the Roborun utility, four additional acceleration steps can be selected between the six ones selectable using the switch, extending the slowest acceleration to 2.04 seconds from 0 to max speed. See “Power Set- tings” on page 182 for details on how to configure this parameter using Roborun.

Important Warning

Depending on the load’s weight and inertia, a quick acceleration can cause consider- able current surges from the batteries into the motor. A quick deceleration will cause an equally large, or possibly larger, regeneration current surge. Always experiment with the lowest acceleration value first and settle for the slowest acceptable value.

Command Control Curves

The AX2550 can also be set to translate the joystick or RS232 motor commands so that the motors respond differently whether or not the joystick is near the center or near the extremes.

The controller can be configured to use one of 5 different curves independently set for each channel.

The factory default curve is a “linear” straight line, meaning that after the joystick has moved passed the deadband point, the motor’s speed will change proportionally to the joy- stick position.

Two “exponential’ curves, a weak and a strong, are supported. Using these curves, and after the joystick has moved past the deadband, the motor speed will first increase slowly, increasing faster as the joystick moves near the extreme position. Exponential curves allow better control at slow speed while maintaining the robot’s ability to run at maximum speed.

Two “logarithmic” curves, a weak and a strong, are supported. Using these curves, and after the joystick has moved past the deadpoint, the motor speed will increase rapidly, and then increase less rapidly as the joystick moves near the extreme position.

The graph below shows the details of these curves and their effect on the output power as the joystick is moved from its center position to either extreme. The graph is for one joy- stick only. The graph also shows the effect of the deadband setting.

48 AX2550 Motor Controller User’s Manual Version 1.9b. June 1, 2007