We present a real-time algorithm which can recover the 3D trajectory of a monocular camera, moving rapidly through a previously unknown scene. Our system, which we dub MonoSLAM, is the first successful application of the SLAM methodology from mobile robotics to the "pure vision" domain of a single uncontrolled camera, achieving real time but drift-free performance inaccessible to structure from motion approaches. The core of the approach is the online creation of a sparse but persistent map of natural landmarks within a probabilistic framework. Our key novel contributions include an active approach to mapping and measurement, the use of a general motion model for smooth camera movement, and solutions for monocular feature initialization and feature orientation estimation. Together, these add up to an extremely efficient and robust algorithm which runs at 30 Hz with standard PC and camera hardware. This work extends the range of robotic systems in which SLAM can be usefully applied, but also opens up new areas. We present applications of MonoSLAM to real-time 3D localization and mapping for a high-performance full-size humanoid robot and live augmented reality with a hand-held camera

/pdf/monoslam-real-time-single-camera-slam-ydmj8dc1vj.pdf

MonoSLAM: Real-Time Single Camera SLAM

We introduce a new method of a biped walking pattern generation by using a preview control of the zero-moment point (ZMP). First, the dynamics of a biped robot is modeled as a running cart on a table which gives a convenient representation to treat ZMP. After reviewing conventional methods of ZMP based pattern generation, we formalize the problem as the design of a ZMP tracking servo controller. It is shown that we can realize such controller by adopting the preview control theory that uses the future reference. It is also shown that a preview controller can be used to compensate the ZMP error caused by the difference between a simple model and the precise multibody model. The effectiveness of the proposed method is demonstrated by a simulation of walking on spiral stairs.

/pdf/biped-walking-pattern-generation-by-using-preview-control-of-84qdve2k8v.pdf

Biped walking pattern generation by using preview control of zero-moment point

From exploring planets to cleaning homes, the reach and versatility of robotics is vast. The integration of actuation, sensing and control makes robotics systems powerful, but complicates their simulation. This paper introduces a versatile, scalable, yet powerful general-purpose robot simulation framework called V-REP. The paper discusses the utility of a portable and flexible simulation framework that allows for direct incorporation of various control techniques. This renders simulations and simulation models more accessible to a general-public, by reducing the simulation model deployment complexity. It also increases productivity by offering built-in and ready-to-use functionalities, as well as a multitude of programming approaches. This allows for a multitude of applications including rapid algorithm development, system verification, rapid prototyping, and deployment for cases such as safety/remote monitoring, training and education, hardware control, and factory automation simulation.

V-REP: A versatile and scalable robot simulation framework

It is known that for a large magnitude push a human or a humanoid robot must take a step to avoid a fall. Despite some scattered results, a principled approach towards "when and where to take a step" has not yet emerged. Towards this goal, we present methods for computing capture points and the capture region, the region on the ground where a humanoid must step to in order to come to a complete stop. The intersection between the capture region and the base of support determines which strategy the robot should adopt to successfully stop in a given situation. Computing the capture region for a humanoid, in general, is very difficult. However, with simple models of walking, computation of the capture region is simplified. We extend the well-known linear inverted pendulum model to include a flywheel body and show how to compute exact solutions of the capture region for this model. Adding rotational inertia enables the humanoid to control its centroidal angular momentum, much like the way human beings do, significantly enlarging the capture region. We present simulations of a simple planar biped that can recover balance after a push by stepping to the capture region and using internal angular momentum. Ongoing work involves applying the solution from the simple model as an approximate solution to more complex simulations of bipedal walking, including a 3D biped with distributed mass.

/pdf/capture-point-a-step-toward-humanoid-push-recovery-12jssfk8t5.pdf

Capture Point: A Step toward Humanoid Push Recovery

For 3D walking control of a biped robot we analyze the dynamics of a 3D inverted pendulum in which motion is constrained to move along an arbitrarily defined plane. This analysis yields a simple linear dynamics, the 3D linear inverted pendulum mode (3D-LIPM). Geometric nature of trajectories under the 3D-LIPM and a method for walking pattern generation are discussed. A simulation result of a walking control using a 12-DOF biped robot model is also shown.

The 3D linear inverted pendulum mode: a simple modeling for a biped walking pattern generation

We propose a method of running pattern generation for a humanoid robot using the dynamics of a simple inverted pendulum A dynamic simulation using a model of an actual humanoid robot shows that the robot can perform running by applying a generated pattern with slight modifications From the simulation we evaluate the required performance of actuators for a real running robot

https://www.jstage.jst.go.jp/article/jrsj1983/21/8/21_8_902/_pdf

Running Pattern Generation for a Humanoid Robot

We have developed a software platform, called OpenHRP, for humanoid robotics which consists of a dynamic simulator and motion control library for humanoid robots. This paper attempts to answer a frequently asked question "do the dynamic simulations and the experiments of biped walking of humanoid robots correspond?". Using OpenHRP and humanoid robots HRP-1S and HRP-2P, the comparisons between the simulations and experiments are shown at various aspects.

/pdf/experimental-evaluation-of-the-dynamic-simulation-of-biped-13f97teqp0.pdf

Experimental evaluation of the dynamic simulation of biped walking of humanoid robots

We present a biped walking pattern generation based on a new way of system discretization named spatially quantized dynamics (SQD). In SQD, a continuous system is discretized by a constant unit length along the walk direction, and the dynamics is represented by a recurrence formula for a unit length motion, taking variable period for each cycle. Using SQD modelling, we can generate a biped gait by taking three steps;1)Design a walking pattern only considering kinematics in the sagittal plane, 2) Calculate the ZMP and velocity by optimization of the spatially quantized dynamics, 3) Add hip lateral motion for 3D dynamic balance. It is shown that we can easily generate a biped gait with stretched knees and a gait for large step climbing. The validity of the generated patterns are confirmed by simulations.

Biped walking pattern generation based on spatially quantized dynamics

Introduction à la commande des robots humanoïdes

In this paper, we plan the collision free motion for walking pattern generation of a humanoid robot. Our motion planner can take into account several features of the walking pattern generator. We first run the walking pattern generator by considering the contact wrench applied to the robot and monitor the collision among the links and the environments. Then, we plan the collision free motion for the period of time causing the collision. In our motion planner, we can consider the constraint condition which are the functions of time. Also, for keeping balance of the robot, we plan the motion with keeping the horizontal position of the COG as well as the position/orientation of the feet/hand. The effectiveness of the proposed method is confirmed by simulation and experiment.

Shuuji Kajita

Papers

Running Pattern Generation for a Humanoid Robot

Experimental evaluation of the dynamic simulation of biped walking of humanoid robots

Biped walking pattern generation based on spatially quantized dynamics

Introduction à la commande des robots humanoïdes

Motion Planning for Walking Pattern Generation of Humanoid Robots