Motion Control Instructions Robot Speed A robot move has three phases: an acceleration phase where the robot accelerates to the maximum speed specified for the move, a velocity phase where the robot moves at a rate not exceeding the specified maximum speed, and a deceleration phase where the robot decelerates to a stop (or transitions to the next motion). Robot speed can mean two things: how fast the robot moves between the acceleration and deceleration phases of a motion (referred to in this manual as robot speed), or how fast the robot gets from one place to another (referred to in this manual as robot performance).
The robot speed between the acceleration and deceleration phases is specified as either a percentage of normal speed or an absolute rate of travel of the robot tool tip. Speed set as a percentage of normal speed is the default. The speed of a robot move based on normal speed is determined by the following factors: l The program speed (set with the SPEED program instruction). This speed is set to 100 when program execution begins. l The monitor speed (set with the SPEED monitor command or a SPEED program instruction that specifies MONITOR). This speed is normally set to 50 at system startup(start-up SPEED can be set with the ACE Controller Config Tools).
(The effects of the two SPEED operations are slightly different. See the SPEED program instruction for further details.) Robot speed is the product of these two speeds. With monitor speed and program speed set to 100, the robot moves at its normal speed. With monitor speed set to 50 and program speed set to 50, the robot moves at 25% of its normal speed. To move the robot tool tip at an absolute rate of speed, a speed rate in inches per second or millimeters per second is specified in the SPEED program instruction. The instruction: SPEED 25 MMPS ALWAYS specifies an absolute tool tip speed of 25 millimeters per second for all robot motions until the next SPEED instruction.
In order for the tool tip to actually move at the specified speed: l The monitor speed must be 100. l The locations must be far enough apart so that the robot can accelerate to the desired speed and decelerate to a stop at the end of the motion. Robot performance is a function of the SPEED settings and the following factors: l The robot acceleration profile and ACCEL settings. The default acceleration profile is based on a normal maximum rate of acceleration and deceleration. The ACCEL command can scale down these maximum rates so that the robot acceleration and/or deceleration takes more time.
You can also define optional acceleration profiles that alter the maximum rate of change for acceleration and deceleration eV+Language User's Guide, v2.x, 18318-000 Rev A Page 121