Koichi Oka

Recognition and cutting system of sweet pepper for picking robot in greenhouse horticulture

This paper describes recognition and cutting system of sweet peppers for picking robots in greenhouse horticulture. This picking robot has an image processing system with a parallel stereovision, a camera positioning system to follow the sweet pepper by visual feedback control, and a cutting device. A prototype robot system has been made and is introduced. Experiments of the prototype prove that performance of the cutting system depends on recognition of fruits of sweet peppers. Consequently, the robot has ability for picking sweet peppers.

Improvement of the Ability to Recognize Sweet Peppers for Picking Robot in Greenhouse Horticulture

This paper describes improvement of the ability to recognize sweet peppers for picking robot in greenhouse horticulture. A prototype of the picking robot for sweet peppers has been manufactured. This robot has an image processing system, a camera positioning system, and a cutting device. However the ability to recognize sweet peppers was low, the picking ability was also low. The color of fruits of sweet peppers is almost same color of leaves of it. For identifying a fruit from leaves, this system needs the lighting system. At first we used the fluorescent lamp on the lighting system. In this system, it was possible to identify only fruits in the condition of mixed fruits and leaves. However, if the fruits overlapping with several other fruits, the shapes of these fruits did not exactly recognize, and it is possible to be different the two fruits that are recognized by right and left camera. In this case, because it cannot to exactly measure by stereovision system, the picking ability became low. So we use the new lighting system with LED. In the result of experiments, this CDD lighting system improves the ability to recognize the sweet peppers

A miniaturized levitation system with motion control using a piezoelectric actuator

A microlevitation system utilizing a permanent magnet attached to a linear actuator is proposed for the purpose of micromanipulation. The air gap length between a small iron ball and a permanent magnet is adjusted to balance the magnetic force and gravity force. A piezoelectric actuator is used to control the air gap length because of its simple construction and low potential for thermal problems. A small iron ball 2.0 mm in diameter was successfully levitated about 40 /spl mu/m from the starting position. The time constant was within the range of 20 ms. This success should contribute to future efforts that utilize electrostatic or intermolecular forces for the noncontact suspension.

A distinction method for fruit of sweet pepper using reflection of LED light

This paper describes a distinction method for fruit of sweet peppers, which are grown in greenhouse, using reflection of LED light. Distinction for fruit of sweet pepper is necessary for development of picking robot in greenhouse horticulture. We have been manufactured a prototype of picking robot for sweet peppers. This picking robot has an image processing system using a parallel stereovision, a positioning system to the recognized sweet pepper using visual feedback control, and a cutting device. However, the distinction ability is lacking. We proposed a distinction method for fruits of sweet pepper using reflection of LED light. Experiments were carried out in greenhouse. In consequence, it was possible to improve the distinction ability.

ADDITIONAL DESIGN FEATURES OF A MASTER–SLAVE CONTROL SYSTEM WITH FORCE SENSING AND ENERGY RECYCLING FOR UPPER LIMB REHABILITATION ROBOTS

Traditional upper-limb rehabilitation robots usually realize force feedback with force sensors or impedance controllers. Otherwise, assistant or resistant force required in different training modes is given by the robot, which does not motivate the initiative of patients sufficiently. This article introduces a self-controlled upper-limb rehabilitation robot to implement force sensing without a force sensor or an impedance controller. The system supports bimanual exercises in different training modes with one limb providing a proper force for the contralateral limb. The above characteristics and the capability of master–slave motion tracking with a kind of energy recycling were verified with preliminary experiments.

3D pose estimation of green pepper fruit for automated harvesting

Method for green pepper pose estimation is proposed.Fruit pose estimation is essential for automatic harvesting.Method uses model matching to fruit surface points.Surface points are obtained by laser range finder.Stem position for cutting can be calculated from fruit pose. This paper presents a novel pose estimation algorithm for stem position detection in Japanese green pepper automatic harvesting. When the available visual cues do not provide sufficient information to the harvesting robot, information about the pose of the fruit in space is necessary for accurate stem position detection. In the proposed method the orientation of a fruit in space is obtained by fitting a model to surface points of the fruit. These surface points are acquired using a Lidar type laser range finder, and the point matching is performed using a coherent point drift algorithm with two model transformation methods, rigid and affine. The performance of the proposed method was evaluated both under laboratory conditions and in a greenhouse. In the laboratory test, the mean total error for the affine transformation was less than 25mm in 42 of 49 positions, less than 20mm in 28 of 49 positions and less than 15mm in 19 of 49 positions. For the rigid transformation, the same error was less than 25mm in 39 of 49 positions, less than 20mm in 31 of 49 positions and less than 15mm in 11 of 49 positions. The total error of the affine transformation was found to be proportional to the inclination angle, as the mean error was 11mm, 15mm, and 23mm for inclination angles of 15, 30 and 45 degrees, respectively. No relationship was found between the mean total error and the inclination angle for the rigid transformation, as the calculated mean total error was 20mm, 18mm, and 20mm for inclination angles of 15, 30 and 45 degrees, respectively. In the greenhouse test, the stem was calculated to be within the cutting range for 81 of 107 instances for affine transformation and for 66 of 107 for rigid transformation. These results suggest that the proposed method is suitable for stem position detection in the automatic harvesting of green pepper, and could be adjusted for use with other fruits and vegetables.

A self-controlled robot for upper limb rehabilitation

The number of hemiplegic patients with a unilateral-disabled limb has been increasing globally, this stimulate the development of rehabilitation robots that assist patients in motor function recovery and strength enhancement. However, as yet, few robots have achieved self-controlled rehabilitation training, and force feedback is generally realized with force sensors. This paper introduces a self-controlled master-slave system implementing force sensing without any force sensor for training patients with limited upper extremity function. The system contains two identical motors that have a directly wired connection. One limb controls the master motor to generate electrical energy, which is recycled to power the slave motor. The slave motor in turn works in electromotive state and supports the other limb to mirror the movement of the contralateral limb. Thus, self-controlled rehabilitation training is realized. An experimental prototype has been developed and the test results confirm that the system can achieve force sensing without a force sensor and realize motion tracking with a kind of energy recycling. Overall, the system has great potential for self-controlled rehabilitation training in the home environment.

Design concept and analysis of a magnetically levitated linear slider with non-contact power transfer

This paper presents the design concept of a magnetically levitated linear slider with non-contact energy transfer, and an analysis of the major components of the design. An open-end generator is introduced to achieve non-contact energy transfer to the levitated platform. Utilization of non-contact energy transfer will overcome difficulties related to charging batteries. Furthermore, we have proposed an improvement for a hybrid electromagnet to achieve better passive lateral alignment under zero power control. The results of FEM analysis and practical testing show that the concept is promising for further study with a prototype system.

2 DOF non-contact magnetic suspension system: A feasibility study

This paper describes 2 types of 2 DOF magnetic suspension systems which suspend two iron balls or an iron stick type object. Both suspension system controls 2 DOF of suspended object(s). The magnetic suspension forces are controlled by a generator of magnetomotive force. This suspension system must control two degrees of freedom without mechanical contacts. In iron stick suspension system, a vertical displacement and a horizontal rotation of the object should be controlled. This paper proves the feasibility of these noncontact suspension systems. A theoretical analysis will be done on the model of these suspension systems and numerical simulations carried out for confirmation of performances.

Air Traffic Efficiency Analysis of Airliner Scheduled Flights Using Collaborative Actions for Renovation of Air Traffic Systems Open Data

The increase in air traffic worldwide requires improvement of flight operational efficiency. This study aims to reveal the potential benefits, namely, savings on fuel consumption and flight time, which are expected for Japanese airspace, by statistically evaluating the operational efficiency defined by average differences of fuel consumption, flight time, and flight distance between the original and the optimized flight of domestic flights in Japan. The aircraft position and time data used in this study were obtained from Collaborative Actions for Renovation of Air Traffic Systems Open Data—the radar data released by the Japan Civil Aviation Bureau. Flight information, such as air data and fuel flow, is estimated by applying meteorological data and aircraft performance model to the position information of radar data. Each reconstructed trajectory is optimized in terms of flight fuel consumption and flight time with an assumed cost index (CI). Dynamic programming is used as the trajectory optimization method. The flight fuel consumption and flight time of the optimized flight are compared with the original values to evaluate the operational efficiency. Herein, approximately one-third of 1-day data, i.e., 1087 cases of four aircraft types, are analyzed with reasonable CI settings. Our research findings suggest that flight fuel consumption and flight distance can be saved by 312 kg and 19.7 km, respectively, on average for the object flights. Following a statistical comparison between the original and the optimized flights, it was observed that two types of features, namely, flying on a detoured path and flying with nonoptimal altitude and speed in the cruise phase, are major factors which deteriorate the total operational efficiency in terms of fuel consumption, flight time, and flight distance.