From Khoo: The degree of spasticity in patients with neuromuscular disorders can be quantified with the...

 

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From Khoo: The degree of spasticity in patients with neuromuscular disorders can be quantified with the use of the "pendulum test." In this clinical procedure, the subject sits relaxed on a table with his lower leg initially supported by the medical examiner so that the knee joint is fully extended. The examiner abruptly releases the lower leg so that it swings freely until it finally comes to rest in the vertical position. The trajectory of the swing, as measured by the change in angle of knee flexion can reveal information about the neuromuscular stretch reflex. Modify the SIMULINK program "nmreflex.mdl" so that it can be used to simulate this test. Note that the major difference between the pendulum test and the procedure described in Section 4.6 is that, here, the externally applied moment does not remain constant but varies according to the angular displacement of the lower leg, since it is a function of the weight of the lower leg and the moment arm between the center-of- gravity of the lower leg and the knee joint. Assume the same parameter values used in "nmreflex.m", except for the following: moment of inertia of the lower leg about the knee joint = 0.25 kg m2; length of lower leg = 40 cm, weight of lower leg = 5 kg. Determine how the trajectory of the lower leg would change with different values of stretch reflex gain . We will break this into 2 parts. A) The first is like described above, but the person is asked to keep their leg extended horizontally. Specifically, we need to replace a step input in torque of Mx = 5 N, with a torque value that depends on the following: My = (1-sin[0]). where L = 40 cm, m = 5 kg,J = 0.25 kg m,g = 9.81 m/s. Extend the simulation time to 5 seconds. Plot the response for values of = 50, 100, 150. What is the final steady state angle achieved for each case of ? B) The second is like described above, with the person told to let their leg fall to vertical. Modify the Simulink file to do this. Plot the response. What is the final steady state angle achieved in this case? From Khoo: The degree of spasticity in patients with neuromuscular disorders can be quantified with the use of the "pendulum test." In this clinical procedure, the subject sits relaxed on a table with his lower leg initially supported by the medical examiner so that the knee joint is fully extended. The examiner abruptly releases the lower leg so that it swings freely until it finally comes to rest in the vertical position. The trajectory of the swing, as measured by the change in angle of knee flexion can reveal information about the neuromuscular stretch reflex. Modify the SIMULINK program "nmreflex.mdl" so that it can be used to simulate this test. Note that the major difference between the pendulum test and the procedure described in Section 4.6 is that, here, the externally applied moment does not remain constant but varies according to the angular displacement of the lower leg, since it is a function of the weight of the lower leg and the moment arm between the center-of- gravity of the lower leg and the knee joint. Assume the same parameter values used in "nmreflex.m", except for the following: moment of inertia of the lower leg about the knee joint = 0.25 kg m2; length of lower leg = 40 cm, weight of lower leg = 5 kg. Determine how the trajectory of the lower leg would change with different values of stretch reflex gain . We will break this into 2 parts. A) The first is like described above, but the person is asked to keep their leg extended horizontally. Specifically, we need to replace a step input in torque of Mx = 5 N, with a torque value that depends on the following: My = (1-sin[0]). where L = 40 cm, m = 5 kg,J = 0.25 kg m,g = 9.81 m/s. Extend the simulation time to 5 seconds. Plot the response for values of = 50, 100, 150. What is the final steady state angle achieved for each case of ? B) The second is like described above, with the person told to let their leg fall to vertical. Modify the Simulink file to do this. Plot the response. What is the final steady state angle achieved in this case?