申論題

2. (35%) A scotch yoke mechanism is shown in Fig. 2. The spring is unstretched when link 2 lies horizontally (θ2 = 0). The spring stifiness is 50 N/m. The length of Link 2 is 1 m. Link 2 is assumed to be massless. Link 3 and Link 4 weigh I kg and 3 kg, respectively. There is no friction in the sliding pairs.

(b) (25%) A motor is installed at the joint between the ground and link 2 to drive link 2 at a constant speed of 10 rad/s in the counter-clockwise direction. Draw the free body diagrams of link 2 and 3 when θ₂ = 30° and determine the torque applied on link 2 by the motor.