Page 33 - Electric Drives and Electromechanical Systems
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Chapter 1   Electromechanical systems  25
























                 FIG. 1.13 Kinematic design of three jointed legs used in robotic applications. (A) Robotic leg that can be used in
                 walking robots inspired by mammals. (B) Robotic leg that can be used in walking robots inspired by insects.


                   A related application is the use using powered exoskeletons as part of the treatment of
                 patients during rehabilitation following a stroke or spinal cord injury. The exoskeletons
                 are effectively walking robots that are designed to support the patient and aim to
                 enhance the rehabilitation process.

                 1.4 Automotive applications

                 The current automotive market is in a state of considerable flux, with rapid advances in
                 autonomous vehicle technology, as well as the goal of reducing our dependence on
                 petrol and diesel. In both cases considerable use is made of electromechanical actuators
                 to operate a range of function. In the electric car the prime mover is an electric motor.

                 1.4.1  Conventional vehicles

                 In the majority of cars electric motors undertake functions that were either formerly
                 considered the domain of mechanical linkages or to provide additional features that
                 increase driver comfort or safety. The conventional brushed d.c. motors, can be found
                 in body and convenience areas, for example windscreen wipers and electric windows.
                 Increasingly brushless motors are also being used in open loop pump drives and air
                 conditioning applications. It is estimated that on average a modern car has over 40
                 individual motors, Fig. 1.14. With the rapid introduction of autonomous systems in to
                 vehicles systems such as intelligent brake-control, throttle-by-wire and steer-by-wire
                 that require a sensor, a control unit and an electric motor. It has been estimated that
                 the electrical load in a car will increase from to around 2.5 kW, with a peak value of over
                 12 kW. This implies that the electrical system will have to be redesigned from the
                 current 12 V d.c. technology to use at higher voltages. One of the possible options is a
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