有時文字能使『學問』感覺簡單了！一門『描述運動』之

運動學

運動學（kinematics）是力學的一門分支，專門描述物體的運動，即物體在空間中的位置隨時間的演進而作的改變，完全不考慮作用力或質量等等影響運動的因素。運動學與力動學、動力學不同。力動學專門研究造成運動或影響運動的各種因素。動力學綜合運動學與力動學在一起，研究力學系統由於力的作用隨著時間演進而造成的運動。^[1][2]

在開始研討古典力學時，很自然地應該先思考各種可能的運動樣式，而暫時不將任何造成運動的因素納入考量。這初步探詢的知識就是運動學的學術領域。— 愛德蒙·維特克，質點與剛體分析動力學通論

任何一個物體，像是車子、火箭、星球等等，不論其尺寸大小，假若能夠忽略其內部的相對運動，假若其內部的每一部份都是朝相同的方向、以相同的速度移動，那麼，可以簡易地將此物體視為質點 ，將此物體的質心的位置當作質點的位置。在運動學裏，這種質點運動，不論是直線運動或是曲線運動，都是最基本的研究對象。

假若不能忽略物體內部的相對運動，則當解析其運動時，必須先將物體理想化為剛體，即一群彼此之間距離不變的質點。涉及剛體的問題比較困難。剛體可能會進行平移運動、旋轉運動或兩者的綜合。更困難的案例是多剛體系統的運動。在這系統內，幾個剛體由機械連桿連結在一起。運動學分析某連桿裝置的可能運動範圍，或反過來，設計滿足預定運動範圍的連桿裝置。起重機或引擎活塞系統都是簡單的運動系統。起重機是一種開運動鏈。活塞系統是四連桿組的一部分。

掛在重力式摩天輪邊緣的乘客座艙在做平移運動

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Kinematics

Kinematics is a branch of classical mechanics that describes the motion of points, bodies (objects), and systems of bodies (groups of objects) without considering the mass of each or the forces that caused the motion.^[1][2][3] Kinematics, as a field of study, is often referred to as the “geometry of motion” and is occasionally seen as a branch of mathematics.^[4][5][6] A kinematics problem begins by describing the geometry of the system and declaring the initial conditions of any known values of position, velocity and/or acceleration of points within the system. Then, using arguments from geometry, the position, velocity and acceleration of any unknown parts of the system can be determined. The study of how forces act on masses falls within kinetics. For further details, see analytical dynamics.

Kinematics is used in astrophysics to describe the motion of celestial bodies and collections of such bodies. In mechanical engineering, robotics, and biomechanics^[7] kinematics is used to describe the motion of systems composed of joined parts (multi-link systems) such as an engine, a robotic arm or the human skeleton.

Geometric transformations, also called rigid transformations, are used to describe the movement of components in a mechanical system, simplifying the derivation of the equations of motion. They are also central todynamic analysis.

Kinematic analysis is the process of measuring the kinematic quantities used to describe motion. In engineering, for instance, kinematic analysis may be used to find the range of movement for a given mechanism, and working in reverse, using kinematic synthesis to design a mechanism for a desired range of motion.^[8] In addition, kinematics applies algebraic geometry to the study of the mechanical advantage of a mechanical system or mechanism.

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能有多困難的呢？如果聽聽

Dynamics, Theory and Applications

 

書中，第二章起頭處作者之說法︰

 

怕是不通『運動學』，恐難掌握『動力學』哩！！

因此所以借

pydy/pydy-tutorial-human-standing

PyDy tutorial materials for MASB 2014, PYCON 2014, and SciPy 2014/2015. http://pydy.org

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Example Problem

The tutorial will go through the PyDy workflow in small steps. At the end the students should have a working 3-link 2D inverted pendulum model of a human that can be used for balancing studies. The free body diagram of the model is shown below:

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Notebooks

These are the notebooks for the tutorial.

• [15 min] n00_python_intro.ipynb
• [14 min] n01_dynamics_overview.ipynb
• [ 4 min] n02_problem_introduction.ipynb
• [39 min] n03_kinematics.ipynb
• [18 min] n04_inertia.ipynb
• [25 min] n05_kinetics.ipynb
• [25 min] n06_equations_of_motion.ipynb
• [32 min] n07_simulation.ipynb
• [25 min] n08_visualization.ipynb
• [28 min] n09_control.ipynb

 

串講補充耶？？

• [39 min] n03_kinematics.ipynb

 

也許世間物只要『部件很多』自然『複雜』的乎？！