Ergonomic material handling equipment with computer-controlled servo drives can enhance an operator's lifting capability. By allowing operators to perform super-human lifting tasks, the devices reduce fatigue and lower the risk of back injuries.

Intelligent assist devices (IADs) provide power assistance and motion guidance. Relying on force feedback, IADs respond quickly and smoothly to an operator's touch, amplifying his arm and finger movements. The operator senses little or no time lapse between his actions and the system's responses.

"IADs use sophisticated control algorithms to coordinate system responses with the human's intentions and assist requirements," says Stephen Klostermeyer, director of sales and marketing at Cobotics Inc. (Evanston, IL). "Servo drives provide a faster, more accurate level of performance not possible with traditional pneumatic or hydraulic lift-assist systems."

Klostermeyer claims that conventional pneumatic or fixed-speed electric devices do not deliver rapid, accurate load movement and positioning. Conversely, IADs use novel sensors, such as those designed and patented by Cobotics, to measure the intent of the operator. The result is easier tool and part movement vertically and horizontally, depending on the system implemented.

"For horizontal movement, our cable-based i-Trolley systems include a cable-angle sensor," explains Klostermeyer. "As the operator pushes on the cable-suspended load, the wire-rope cable will deflect off center. The sensor reads that deflection and instructs the servo motor to move in the correct direction." Therefore, the operator exertion required to start and stop large, awkward items or tools is reduced.

Intent sensors combined with control features such as home positioning, which moves an empty tool automatically to a home position, allow the operator to focus on the assembly task. "The operator isn't burdened with the additional steps of returning a tool when he or she is through with it," says Klostermeyer. The operator's movements are dedicated to the assembly task, which translates into greater productivity.

When lifting either tools or parts in the vertical direction, the Cobotics i-Lift automatically compensates to the weight attached to it. "Vertical IADs are like hoists with intelligence on board," claims Klostermeyer. "The operator doesn't have to adjust the lifting device to accommodate changes in the load."

Intelligent assist devices are also available from other vendors. For instance, the G-Force from Gorbel Inc. (Fishers, NY) constantly senses a load and adjusts to changes in load capacity and speed. The company claims that its device "makes any load up to 150 pounds feel like it weighs only 3 pounds. It enables you to lift loads and manipulate objects like it was an extension of your own arm." The device is capable of lifting speeds from 1 foot per minute to 275 fpm.