Kousei Nojiri

Impedance control of CPM device with flex-/extension and pro-/supination for upper limbs

Continuous Passive Motion (CPM) is a surgical treatment or physiotherapy after surgery or trauma. Most of the CPM devices used for treatment of the elbow joint have one degree of freedom in flex-/extension. For this reason, the patients are limited in pro-/supination of the forearm with flex-/extension of the elbow joint according to the arm movement of the CPM device. In this paper, a novel impedance control scheme of pro-/supination is proposed for CPM device with flex-/extension and pro-/supination. Impedance control is designed for the reference trajectory measured from a normal subject, and the parameters for impedance control are designed in order to suppress the excessive force at the limitation of range of motion. The effectiveness of the proposed scheme is evaluated by experiments.

On effective movement in CPM for shoulder joint

Continuous passive motion (CPM) is an orthopedic treatment or physiotherapy method that promotes recovery of impaired joints, and is tried to apply for treatment of the shoulder joint disorders. The shoulder joint has a complex structure, where the inner/outer rotation torque of the shoulder joint varies due to ad-/abduction angle. Wrong ad-/abduction angle causes the excessive inner/outer rotation torque of the shoulder joint, and aggravates joint disorders. So, it is required to adjust suitably the ad-/abduction angle to suppress the inner/outer rotation torque. In this paper, the ad-/abduction motion that suppresses the inner/outer rotation torque is clarified. The variation of the inner/outer rotation torque due to ad-/abduction angle is analyzed in experiments with fixed ad-/abduction. From the experiments, we clarify the ad-/abduction motion suppressing the inner/outer rotation torque. To realize the clarified ad-/abduction motion, we developed the CPM device that has two d.o.f with the inner/outer rotation and the ad-/abduction. Finally, the experiment with the CPM device is performed in order to confirm that this motion is effective to suppress the excessive inner/outer rotation torque of the shoulder joint.

Modeling of pro-supination for forearm skeleton based on MRI

Abstract The continuous passive motion (CPM) device we developed for the elbow joint implements pro-supination of the forearm naturally accompanying flexion and extension of the elbow joint. As the method of making the curative effect due to accompanying pro-supination clear, the range of motion (ROM) of the forearm skeleton are estimated by using of the pro-supination model of the forearm skeleton. As the pro-supination model of the forearm skeleton, there are the models Fick and others and Kecskemethy and others proposed. But, hypothesis is set in regard to the link length of the model and the rotation axis of the forearm. So, in the case of pro-supination of the forearm, it is thought that mismatch happens between the forearm skeletal model and the forearm skeleton. In this paper, by analyzing magnetic resonance imaging (MRI) of the forearm, we proposed the newer forearm skeletal model based on the biomechanics.

Impedance control of pro-/supination based on the skeleton model of upper limbs

Continuous passive motion (CPM) is an orthopedic treatment or physiotherapy method after surgery or injury by external continuous force. In CPM for the elbow joint, it is effective to reduce an excessive reaction force from a subject by controlling pro-/supination of forearm. The ulna collateral ligament in the elbow joint is extended due to pro-/supination of forearm, and it appears that extension of the ligament aggravate contracture disorders. Thus, it is required to suppress the excessive extension of the ligament. In this paper, an impedance control which suppress the excessive extension of the ligament due to the pro-/supination of CPM device is proposed, and the trajectory of extension of the ligament while CPM training with proposed controller is clarified by skeleton model.

Impedance control of CPM device with flex-/extension an pro-/supination of upper limbs

Continuous passive motion (CPM) is an orthopedic treatment or physiotherapy after injury or operation. Most of CPM devices used for treatment of the elbow joint have one degree of freedom in flex-/extension. This causes that the patients are limited in pro-/supination of the forearm with flex- /extension of the elbow joint due to the movement of CPM device. In this paper, a novel impedance control scheme of pro- /supination is proposed for CPM device with flex-/extension and pro-/supination. Impedance control is designed for the reference trajectory measured from normal subject, and the parameters for impedance control are determined in order to suppress the excessive force at the end of the range of motion. The effectiveness of the proposed scheme is evaluated by experiments.

Motion direction estimation of walking base on EEG signal

In this paper, we propose the method to estimate the motion direction of walking based on brain wave activity. The signals of 11-channel as Electroencephalogram (EEG) of a motor area are measured to estimate the direction of a walking. After measuring the signals of 11-channel related to the motion of the lower limb, the several signal processing algorithm are applied for the signals. Specifically, we have used band pass filter to cut off the signal other than between 5-35[Hz], JADE as a form of Independent Component Analysis (ICA) and Multi-class Support Vector Machine (SVM) as a motion classifier. The interval of a motor area about the lower limb at two sides of the brain is very near and a motor area about it is located behind skin of scalp. Therefore, it is difficult for us to measure the EEG and cut off noises. However, we think that our proposal algorithm is effective to develop the real-time Brain Machine Interface (BMI). We performed the experiment that one subject lying down on a bed with closed eyes images the motion of walking, standing and turning the left and right direction among interval of 30 seconds, respectively. As the result of applying our algorithm, the recognition rate within 50-60[%] was achieved. But, it is necessary to increase number of subject, to verify the algorithm and to raise the precision of the rate. The final target is to reveal the estimation method of motion direction of walking by means of several kinds of experiments.

Impedance Control of Two d.o.f CPM Device for Upper Limb Disorders

Abstract Continuous passive motion (CPM) is an orthopedic treatment or a physiotherapy and is tried to apply after surgery for the injured radial collateral ligament (RCL) in the elbow joint. After the surgery, the reaction force at hand of the patient increases due to an increase of the joint stiffness and may be excessively large. For this, it is effective to reduce the excessive reaction force by controlling pro-/supination of forearm. Also, the RCL in the elbow joint is extended due to pro-/supination of forearm, and the extension may aggravate the injury of the RCL. Thus, it is required to suppress both the excessive extension of the RCL and the reaction force. In this paper, a novel impedance control of CPM device that can suppress both the excessive extension of the RCL and the reaction force is proposed.

Inverse Kinematics Analysis of Forearm in CPM Based on Biomechanics

Continuous passive motion (CPM) is a surgical treatment or physiotherapy after operations for disorders. In the rehabilitation with the CPM device for the upper limb, because the musculoskeletal structure of the upper limb is not clarified, the relationships between the upper limb joint and CPM are not analyzed. Especially, the joint angle information by accompanying pronosupination of the forearm is not clear. In this paper, a method using the wrist direction vector for calculating inverse kinematics of the forearm is proposed and applied to pronosupination model based on the biomechanics. In addition, the results are verified by comparing with the measure result of the forearm.

Inverse Dynamics Analysis of Forearm in CPM

In the rehabilitation with the continuous passive motion (CPM) device for the upper limb, the musculoskeletal structure of the upper limb has not been clarified. In this paper, we regard the forearm as a skeleton model with an elastokinematic coupling between axial displacement and lateral swaying of the humero-ulnar (elbow) articulation. The solution of the inverse dynamics is obtained by using the geometric constraint, and validity of the inverse dynamics is evaluated by simulation