This paper describes a method of generating low-distortion sinusoidal waves using an arbitrary waveform generator (AWG), and experimental results of using such a generator for ADC dynamic performance testing. With this proposed method, 3rdorder harmonics of the generated signal are suppressed simply by changing the AWG program (or waveform memory contents)-AWG nonlinearity identification is not required-and spurious components, generated far from the signal band, are relatively easy to remove using an analog filter; our theoretical analyses, simulations, and experiments showed that a simple passive LC analog filter (with relaxed requirements compared to the one for direct HD3 removal) is sufficient. Our ADC testing results-using signals generated by an AWG with the proposed algorithm, and a simple passive LC LPF-show measurement errors (caused by 3rdorder harmonics generated by AWG DAC nonlinearity) half that of previous algorithms.

This paper describes algorithms for generating low intermodulation-distortion (IMD) two-tone sinewaves, for communication application ADC testing, using an arbitrary waveform generator (AWG) or a multi-bit ΣΔ DAC inside an SoC. The nonlinearity of the DAC generates distortion components, and we propose here eight methods to precompensate for the IMD using DSP algorithms and produce low-IMD two-tone signals. Theoretical analysis, simulation, and experimental results all demonstrate the effectiveness of our approach.

We have developed a new biped foot mechanism capable of detecting ground surface to realize stable walking on uneven terrain. The size of the foot mechanism is 160 mm × 277 mm and its weight is 1.5 kg. The foot system consists of four spikes each of which has an optical sensor to detect ground height. The foot makes a support polygon on uneven terrain by using three or four spikes. We have conducted several experiments on the outdoor ground surface that has a slope of 7.0 degrees and a maximum height of 15 mm bumps, and the effectiveness of the foot mechanism is confirmed.

This paper presents a quadruped-walking robot for demining mission. Robot that can adapt any landscape and handle various tasks by utilizing the legs as manipulator is useful one to ensure the safety of local residents and people engaged in the demining mission. However, it is known that mine removing by human workers is progressing slowly because of the risk of their lives. The proposed robot has various features, such as 1) much wider working area than conventional walking robots, 2) unique drive mechanism, 3) high modularity and cooling mechanism and so on. It is expected to give the workers safety to accelerate the demining.

We have been developing a small biped entertainment robot and expanding its capabilities for adaptability and mobility in the home environment with enhanced core technologies. Conspicuous enhancements are a new robot actuator, ISA and Real-time Integrated Adaptive Motion Control System as a comprehensive motion control for SDR to realize the dynamic and smooth/elegant motion performances. In order to evaluate the basic motion control capabilities we propose a new motion evaluating system for a small biped entertainment robot. The system is composed of the SDR Motion Base and the control system. We have developed a serial-parallel hybrid type mechanism to apply for the basic experiment of SDR's motion control capabilities. We discuss the design concept of the motion evaluating system and the experimental method using the proposed Motion Base.

Though development of a practical walking robot is not easy at all, walking robots have many practical advantages resulting from moving functions peculiar to this type of robots including excellent moving characteristics and working characteristics on uneven land. It is cited as a worldwide problem that presently, many antipersonnel mines still remain buried everywhere in the world after the wars injuring many civilians. From humanitarian view points, establishment of a technology which ensures effective removal of mines with safe and inexpensive manner by civilians instead of very dangerous mine removal works done directly by hands is needed. Of specific features shared by walking machines, the authors have been developing a walking type work robot. This robot can walk freely around a buried mine area under extremely severe environments and carry out a series of works such as removal of obstacles before mine removal works, removal of shrubs, mine probing and eventual mine removal. The paper introduces the walking machines developed by the authors so far, a walking type mine removal robot being developed extensively at present and discusses themes and views of development of a practical type walking robot in the next generation which ensures stable movement and works on uneven land. The concept of development of a robot which will be engaged in probing and removal of mines from humanitarian view points is discussed too.

As one of the essential technologies to realize a demining robot, which has the function of searching task for the mines during an autonomous phase and digging task for the mine in a tele-operated phase, we propose the shape-feedback master-slave arm. Feature mechanism of shape-feedback master and slave arm is the articulated finger joints located in the middle of master and slave fingers and their unilateral control to drive master finger joints to have same angle with the slave finger joints, which bend with compliance. Addition of these finger joints under unilateral control of the gripper with conventional bilateral servo control, it is expected to improve the performance of master-slave arm. We demonstrated the validity of the "shape-feedback" master and slave arm by the basic operation experiments and experiments using the model of demining robot.

This paper proposes a quadruped-walking robot that performs "humanitarian demining" tasks. We have already proposed the basic concept of the humanitarian demining robot system, and have several experiments of the operation using the first prototype robot system, VK-I. To accomplish the tasks, we develop several end effecters that can be attached to the working leg. After these basic experiments, we consider to modify the concept, phases of the tasks and to develop the next prototype robot system that will have better performance. The robot will be given a "foot-end-effector changing system" on its back so by utilizing the legs as manipulation arms and connecting various tools (foot-end-effectors) to the foot of the working leg, it can perform all of the procedure of the demining tasks. We discuss the advance of our study and introduce next concept called VK-II.

Proposes a quadruped walking robot which performs mine detection and removal tasks. Because there are many personnel mines remaining from wars, it is desirable to provide a safe, inexpensive tool which civilians can use to remove these mines. The robot has a tool changing system on its back, so by utilizing the legs as manipulation arms and connecting various tools to the foot, it can perform mine detection and removal tasks. For these tasks, we developed the shape-feedback master-slave arm as a kind of basic technology. When a contact force is applied to the slave arm, the shape of the slave is transmitted to the master arm. We can estimate the force from this shape. We discuss the basic design concepts of the robot system and the shape-feedback controlled gripper.