Solution Of IK Problem And Research Of Walking Motion Control In Virtual Human

To study the Behavioral-Characteristic Modeling for Distributed Interactive 3D Scenery Generation, we emphasize the human motion being regarded as a typical motion. The human skelecton modeling, IK and human walking are the primary studying.The first thing we must do is human body modeling. Here we give a model in the aspact of skelecton. We need abstract and simplift body structure because of its complexity. And we give a hierarchical structure of the body model to describe the human motion clearly. Human Skelecton model is composed of joints and bones.We classify human joints with three models according to their rotational degree of freedom by analyzing their character. They are joints of one rotational degree of freedom(one DOF), two rotational degree of freedom(two DOF) and three rotational degree of freedom(three DOF).The hierarchical structure of the human body is a tree structure. Each node has only one parent, and the root node has no parent. The parent and child of a joint is bone, and each joint has only one child. Bone's parent and child is joint, and a bone maybe has many children, the hip bone has three children joints for instance. There are 23 joints and 23 bones being defined. The root bone is hip and its parent is root joint who is defined in world coordinate and is the root of the tree. All the leaves are bones. There are 57 rotational DOF in the human tree structure.IK is the abbreviation of Inverse Kinametics. In the body hierarchical structure, the joints and bones constitute the motion chain. For example, shoulder joint, elbow joint, wrist joint and their child bone make up a motion chain which is a branch of the whole human motion chain. We can control human motion through these chains. Kinametics has two forms which are direct kinametics and inverse kinametics. The problem that we know the rotational degree of everyjoint and we need resolve the position of a joint or the end effector belongs to direct kinametics problem. But the problem if we know the position of the end effector, we need resolve the rotational degree of every joint belongs to inverse kinametics problem.The method of solving IK problem called Pointing-Line is put forword in our laboratory. It is similar to a method called Cyclic-Coordinate-Descent which is put forword by a foreign scholar. It's a iterative and heuristic technique. Every time it change the rotational degree of one joint in the motion chain orderly and makes it to approach the end effector. It's factly a numerical solution.The motion of human walking is cyclic activity. A duration walking cycle is broken down into duration of single support and duration of double support. The walking parameters consist of stepspace, walking speed and so on. Gesture parameters include swing amplitude of head and arms, splayfoot etc. Our method is similar to Key-Frame to implement walking. It breaks down the movement of a cycle into ten key actions. These key actions can be gained by resolving IK problem. The action between two key actions can be resolved by interpolating. The kinematics is the base. Five IK chains are used to implement the walking motion. They are Left-Arm chain, Right-Arm chain, Left-Leg chain, Right-Leg chain and Head chain.