MOTORS, DRIVES & CONTROLS
SECTION TITLE
LOW PROFILE BRAKE DESIGNS Recent advancements have enabled robotic
arms and mechatronic systems to shrink in size. Tis reduction in footprint often requires low profile or ‘pancake’ style brake technology. KEB has recognised the increasing demand for compact spring applied brakes and has successfully designed custom low-profile brakes. Tis style of brake is functionally identical to the standard spring applied brake but achieves the same rated torque in approximately two- thirds the thickness, which allows for highly compressed drive system braking in robotic joints, AGV’s, forklift trucks, etc. Magnetic simulation software can also be used to design custom brakes that meet customer- specific design envelope constraints.
INCORPORATING THE BRAKE OR HAVING IT SEPARATELY? Not all robotic applications require the brake to be incorporated into the robot arm, which means the size of the brake itself is less critical. In some cases, such as torque motors or hollow shaft motors, the brakes will have to be mounted separately. However, size of the brake is still important for all applications.
In medical units such as a surgical operating arm, the brake can also act as the clutch. Te brake holds the robot arm in place but if the maximum torque limit is reached, the unit can be moved (i.e. pushed out of the way) but still held safely. Often, the friction material can affect or control this, which is a good safety aspect.
OTHER DESIGN OPTIONS Other features can be added to brakes used in compact robotic applications. Tese in- clude reduced holding voltage – after being released at nominal voltage, some manufac- turers of spring applied brakes can drop to a holding voltage of 50% nominal. Tis is very advantageous for an AGV, forklift truck or other mobile robotic application where the power supply is a battery, as power con- sumption is significantly reduced. Tis will also reduce heat generated from the brake coil. Tis is typically achieved with pulse width modulation (PWM) controlled by the customer.
Cable assembly and connectors are another common design option. Some suppliers can provide brakes complete with heat shrink tubing, wire jackets, pig tailed leads, cable labels, etc. Along with added
KEB uses magnetic simulation software to optimise designs
connectors or plugs. Tis eliminates the need for customers to add cable assembly to their process and provides a ‘plug-and-play’ ready solution.
A final design option is custom coil
voltages. some batteries and control systems operate at voltages outside of the common standard offerings (24, 48, 105, 205VDC). Some suppliers can design and wind a coil to suit any desired voltage.
Mark Checkley is with KEB Automation.
www.keb.co.uk
With drives for Mars, every tenth of a gram counts
Aiko Stenzel, Aerospace Design Engineer Our DC motors and gearheads are a part of many space missions. They are developed based on our previous experiences and our knowledge. Aiko knows exactly which modifications are needed for our standard industrial products to function perfectly on Mars. High vibrations and temperature fluctuations? No problem. All of this is achieved with weight requirements that test the limits of what is possible. Our precision and curiosity drive us to excel:
mars.maxonworld.com
Precision Drive Systems
Approved supplier
of mechanism actuators for space exploration missions
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