776 Part D Manipulation and Interfaces Fig.33.4 One-handed upper-extremity exoskeleton where Fig.33.3a,b Two-handed upper-extremity exoskeleton a griper allows for grasping of heavy objects [33.21] where artificially built friction forces between the load and the arms allow for grasping objects [33.25] The upper-extremity exoskeleton will significantly re- duce the incidence of back injury in the workplace, to the magnitude of the worker's force on the device.Al- which will in turn greatly decrease the annual cost of though the worker might be paying very little attention to treating back injuries. the final destination of the seat,the device can still bring Upper-extremity exoskeletons were designed based the seat to its proper place without the worker's guid-primarily on compliance control [33.26-29]schemes ance.The upper-extremity exoskeleton reflects on the that relied on the measurement of interaction force worker's arm forces that are limited and much smaller between the human and the machine.Various experi- than the forces needed to maneuver loads.With it,auto- mental systems,including a hydraulic loader designed assembly and warehouse workers can maneuver parts for loading aircrafts and an electric power extender built and boxes with greatly improved dexterity and preci- for two-handed operation,were designed to verify the sion.not to mention a marked decrease in muscle strain. theories(Fig.33.3 and Fig.33.4). 33.3 Intelligent Assist Device The intelligent assist devices (IAD)are the simplest system includes an ergonomic handle,which contains non-anthropomorphic form of the upper-extremity sys- a high-performance sensor for measuring the magnitude tems that augments human capabilities [33.30,31]. of the vertical force exerted on the handle by the operator. Figure 33.5 illustrates an intelligent assist device (IAD). A signal representing the operator force is transmitted At the top of the device,a computer-controlled elec- to a computer controller,which controls the actuator of tric actuator is attached directly to a ceiling,wall,or the IAD.Using the measurement of the operator force an overhead crane and moves a strong wire rope pre- and other calculations,the controller assigns the neces- cisely,and with a controllable speed.Attached to the sary speed to either raise or lower the wire rope to create wire rope is a sensory end-effector where the opera- enough mechanical strength to assist the operator in the tor hand.the IAD.and the load come into contact.The lifting task as required.If the operator pushes upwardly end-effector includes a load interface subsystem and an on the handle,the assist device lifts the load;and if the operator interface subsystem.The load interface sub-operator pushes downward on the handle.the assist de- Part D33.3 system is designed to interface with a variety of loads vice lowers the load.The load moves appropriately so and holding devices.Hooks,suction cups,and grippers that only a small preprogrammed proportion of the load are examples of other connections to the end-effector as force(weight plus acceleration)is supported by the oper- shown in Fig.33.6.In general,to grab complex objects, ator,and the remaining force is provided by the actuator special tooling systems should be made and connected to of the IAD.All of this happens so quickly that the op- the load interface subsystem.The operator interface sub- erator's lifting efforts and the device's lifting efforts are776 Part D Manipulation and Interfaces a) b) Fig. 33.3a,b Two-handed upper-extremity exoskeleton where artificially built friction forces between the load and the arms allow for grasping objects [33.25] to the magnitude of the worker’s force on the device. Al￾though the worker might be paying very little attention to the final destination of the seat, the device can still bring the seat to its proper place without the worker’s guid￾ance. The upper-extremity exoskeleton reflects on the worker’s arm forces that are limited and much smaller than the forces needed to maneuver loads. With it, auto￾assembly and warehouse workers can maneuver parts and boxes with greatly improved dexterity and preci￾sion, not to mention a marked decrease in muscle strain. Fig. 33.4 One-handed upper-extremity exoskeleton where a griper allows for grasping of heavy objects [33.21] The upper-extremity exoskeleton will significantly re￾duce the incidence of back injury in the workplace, which will in turn greatly decrease the annual cost of treating back injuries. Upper-extremity exoskeletons were designed based primarily on compliance control [33.26–29] schemes that relied on the measurement of interaction force between the human and the machine. Various experi￾mental systems, including a hydraulic loader designed for loading aircrafts and an electric power extender built for two-handed operation, were designed to verify the theories (Fig. 33.3 and Fig. 33.4). 33.3 Intelligent Assist Device The intelligent assist devices (IAD) are the simplest non-anthropomorphic form of the upper-extremity sys￾tems that augments human capabilities [33.30, 31]. Figure 33.5 illustrates an intelligent assist device (IAD). At the top of the device, a computer-controlled elec￾tric actuator is attached directly to a ceiling, wall, or an overhead crane and moves a strong wire rope pre￾cisely, and with a controllable speed. Attached to the wire rope is a sensory end-effector where the opera￾tor hand, the IAD, and the load come into contact. The end-effector includes a load interface subsystem and an operator interface subsystem. The load interface sub￾system is designed to interface with a variety of loads and holding devices. Hooks, suction cups, and grippers are examples of other connections to the end-effector as shown in Fig. 33.6. In general, to grab complex objects, special tooling systems should be made and connected to the load interface subsystem. The operator interface sub￾system includes an ergonomic handle, which contains a high-performance sensor for measuring the magnitude of the vertical force exerted on the handle by the operator. A signal representing the operator force is transmitted to a computer controller, which controls the actuator of the IAD. Using the measurement of the operator force and other calculations, the controller assigns the neces￾sary speed to either raise or lower the wire rope to create enough mechanical strength to assist the operator in the lifting task as required. If the operator pushes upwardly on the handle, the assist device lifts the load; and if the operator pushes downward on the handle, the assist de￾vice lowers the load. The load moves appropriately so that only a small preprogrammed proportion of the load force (weight plus acceleration) is supported by the oper￾ator, and the remaining force is provided by the actuator of the IAD. All of this happens so quickly that the op￾erator’s lifting efforts and the device’s lifting efforts are Part D 33.3