螺旋运动

Another new spatial 3-RPS parallel pyramid manipulator mechanism is studied. The principal screws of this mechanism under three different configurations are identified by means of the conic section and the quadric degenerating theory, respectively. The planar conics representing the relations between the pitches of the output twists and the three linear inputs are described, and the three-dimensional distribution of the axes of all the twists with the same pitch is illustrated under each of the configurations.

研究了另一种新的空间三自由度3-RPS并联角台机构，分别用二次曲线和二次曲面分解法识别该机构在三种位形下的主螺旋，绘制了其在每种位形下的输出运动螺旋的节距与输入之间的平面图以及具有相同节距的所有运动螺旋轴线在每种位形下的空间分布的立体图。

According to the geometrical principle of conical milling cutter with equal helix angle, a new process of rough machining of conical milling cutter with equal helix angle on universal milling machine by using additive equipment is presented.

根据等螺旋锥铣刀几何原理，提出一种借助附加装置在万能铣床上进行等螺旋角锥铣刀粗加工工艺，介绍了该方法加工锥铣刀时工作铣刀的运动方程；给出了附加装置的设计原理，通过对用此方法加工出的铣刀参数进行测试，证明了这种方法的可行性和实用性。

The horizontal universal milling machine technological transformation based on Mitsubishi PLC;2. Analysis of some important points for makinghelical gear on universal milling machine ;3. According to the geometrical principle of conical milling cutter with equal helix angle, a new process of rough machining of conical milling cutter with equal helix angle on universal milling machine by using additive equipment is presented.

根据等螺旋锥铣刀几何原理，提出一种借助附加装置在万能铣床上进行等螺旋角锥铣刀粗加工工艺，介绍了该方法加工锥铣刀时工作铣刀的运动方程；给出了附加装置的设计原理，通过对用此方法加工出的铣刀参数进行测试，证明了这种方法的可行性和实用性。

Instantaneous motions of the end effector of the typical industrial serial 6-DOF and 5DOF robots are also studied using reciprocal screw theory, The constrained and permitted motions at special configurations are given. Furthermore, the satisfied conditions for the special configurations are discussed, and in the reference coordinate system general expressions of the reciprocal screw and existed motion screw and the subspaces of the permitted rotational axes are obtained under all circumstances at special configurations.

本文中还用反螺旋理论研究了六自由度和五自由度工业机器人的瞬时运动，给出了它们在正常位形和特殊位形下的受约束的运动和存在的运动，以及它们在所有运动参数的不同组合下的反螺旋及存在运动螺旋系的一般表达式和转动轴线存在的子空间。

The detail contents can be summarized as follows: Using Grassmann line geometry method to analyze joint axes linear dependence in manipulator singular configurations; The manipulator constrain equations are derived base on the reciprocity of twists and wrenches; The null space method is used to obtain the reciprocal screws when singularity occurs.

具体内容包括以下几个方面：用Grassmann线几何方法分析了机器人机构奇异时关节轴线的线性相关性；用螺旋理论推导出了基于力螺旋和运动螺旋表示的反螺旋约束方程式；用零空间理论求出了机器人奇异位形的反螺旋。

Firstly, the developing principles of the cylindrical internal helical gear are proposed through analyzing the movement and geometry requirements, which provides continuous contact between the mating gear surfaces. The tooth surface of the internal helical gear in the new gearing can be imagined as being generated by the normal section of the conjugated surface of the ball-tooth, moving along the radial projection of helix line of the tooth-root circle. Also, the proposed surface can be approximate tangent to the conjugated surface of the ball-tooth along a spacial curve.

首先，通过分析保证行星轮作螺环运动时与内斜齿轮实现连续啮合传动的运动和几何条件，提出了圆柱内斜齿轮齿面的两种形成原理：即由球齿运动包络曲面的法截面沿其齿根圆螺旋线在径向的投影进行拓展所形成的内齿面，以及与球齿运动包络曲面呈近似相切接触的等螺距齿面构成的内齿面。

Firstly, velocity expression of translational parallel manipulator was presented based on the screw theory. Secondly, the actuated screw, the actively unactuated screws and idle screws of each limb were determined according to the reciprocal screw theory. Then, all basic kinematic chains were enumerated by means of the number of limb connectivity and the limbs containing closed-loops were obtained by replacing the passive prismatic joints in the basic kinematic chains with planar closed-loop structures.

首先基于螺旋理论给出移动并联机构的速度表达式，然后根据互易螺旋理论确定出分支的主动螺旋、可动非主动螺旋和惰性螺旋，再依照分支连接度的不同列举出所有可行的基本分支运动链，并通过运动副替换得到分支中含有闭回路结构的运动链，最后利用所综合出的支链按照主动副的配置要求将动平台和静平台连接起来即可实现预期的机构。

Based on the stress analysis to spired axis mechanism,in the aspect of sliding part which smoothes through alveolus intersection, theresearch of parameters optimization, about the middle alveolus of spired axis andthe dimension of sliding part, has been studied. To the problem that the reverseportion at the both sides of spired axis lashed fiercely and fraies quickly, thearticle finely analyses the best curve of alveolus when adding cushiony spring atthe both sides.

在对螺旋轴机构进行受力分析的基础上，从滑块顺利通过齿槽交叉点的要求方面，对螺旋轴中间段齿槽和滑块的尺寸进行了参数优化分析；针对螺旋轴两端曲线齿槽反向段在高速工作时冲击大、磨损快的问题；从减少滑块在齿槽反向段运动的冲击方面，比较分析了圆弧、抛物线、三角函数等曲线作为螺旋轴齿槽反向段曲线的加速度，提出了较优的(来源：ABCab论bf文网www.abclunwen.com)反向段曲线。

In spheric linkages, the axes of all revolute pairs must intersect at point.

任一包含如螺旋副的机构都是一空间机构，因为螺旋副的相对运动是螺旋的。

The first one is Vector Pursuit which is based on Screw Theory. The second one is Replicate Line Method presented by this thesis which is presented according to the skid-steering property of track-laying mobile robot and the constraint of its working environment. Thirdly, use the path tracking method proposed by Kanayama for reference to control the robot moving for the current position to the desired position with the desired velocity, so make the path tracking process more precise.

然后从运动学方面，根据机器人当前位置与目标点的位置偏差和角度偏差，采用基于螺旋理论的向量追击法，以及本文根据履带式移动机器人运动特点和工作环境特点提出了的轨迹跟踪方法，折线法，来确定机器人的期望运动；再借鉴Kanayama提出的轨迹跟踪控制方法，对机器人以期望运动速度从当前位置运动到目标点的过程进行控制，从而进一步精确了跟踪过程。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失