STEP Six-Axis Robot Soft Floating Function
2025-05-22
The soft-floating function of STEP robots is a technology that enables flexible control between the robot’s end-effector and the workpiece. By reducing the position gain, velocity gain, and compensating torque values of the joint axes, the robot can exhibit smoother and safer motion characteristics when contacting the workpiece, thereby effectively meeting the requirements of flexible operations.
This feature is widely used in die-casting machine moving dies for part removal, machining moving dies, injection molding, and other applications. However, it is not suitable for injection molding machines whose ejector mechanisms exhibit inconsistent ejection forces, as this could lead to mechanical damage. Furthermore, both the soft-floating process and its trajectory must avoid singular points.
Today, in this article, we’ll introduce and share the soft-floating feature of STEP six-axis robot.
User pain points
Assembly operation
Project Challenges
For gear component machining, the clearance between the workpiece and the machine tool spindle should be 0.02–0.04 mm. The clamping allowance is minimal, and the machining accuracy requirements are high.
Solution
• A circulating hopper to handle the initial positioning of workpieces and meet the requirements for loading/unloading as well as 4-hour production needs;
• Self-centering grippers and flexible fingers adapt to the diversity of workpieces and changes before and after machining;
• Soft floating function to address clamping issues, improve clamping success rates, and prevent the robot from squeezing against the machine tool spindle, thereby avoiding damage to the workpiece.
Placement process when soft floating is enabled
Die casting feeding
Project Challenges
When the moving mold ejects the part, the workpiece moves along with the ejection mechanism, and once it reaches a certain position, the workpiece may become detached and fall.
Solution
The soft floating function allows the robot and the workpiece to move together for a certain distance when the workpiece is being ejected by the ejection mechanism, after which the robot removes the workpiece.
Soft floating joint settings
Soft floating Cartesian setting
Implementation approach
By softening the servo PID through adjusting the stiffness of each axis and performing axis torque compensation based on the dynamic model, it is possible to maintain floating follow-up with external contact objects within a specific spatial segment.
Function Description and Setting Statements
Used for robots to move along a specified vector direction under the action of external forces; when the soft-floating function is normally disabled, the servo gradually returns to its state before the soft-servo function was enabled within the set time (the PID parameters gradually increase), and the joint position tracks the commanded position.
Soft floating function setting statement
Comparison of running paths with soft floating function enabled/disabled
The soft-floating function of STEP six-axis robots, with its compliance and adaptability, supports industrial automation production, enhances safety and reliability, optimizes production efficiency and product quality, ensures precise coordination between the robot and external equipment, and delivers highly efficient and flexible automation solutions for enterprises.
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