Please find a practical machine containing a linkage mechanism $($such as those found in construction sites, amusement parks, exhibitions, museums, science

centers, transportation, etc.$),$ and conduct an analysis and synthesis of this machine. The specific requirements include:

$4\mathrm{.}1$ Describe the function and application occasions of the machine;

$4\mathrm{.}2$ Analyze the motion of the mechanism, determine the number of driving links, draw a kinematic diagram of the mechanism, and calculate its degree of freedom;

$4\mathrm{.}3$ Roughly measure and draw the dimensions of the components, and perform the substitution of higher pairs by lower pairs;

$4\mathrm{.}4$ Determine the number and level of the link groups contained in the mechanism $($disassemble the link groups$)$ and judge the level of the mechanism;

$4\mathrm{.}5$ Analyze whether the mechanism has quick$-$return characteristics or dead$-$center positions;

$4\mathrm{.}6$ Conduct motion analysis of the mechanism using the instantaneous center method;

$4\mathrm{.}7$ Conduct motion analysis of the mechanism using the analytical method$)($write out the mathematical model and program flowchart$)$;

$4\mathrm{.}8$ Analyze the advantages and disadvantages of the mechanism and how to improve its deficiencies.

ATTENTION: One person is responsible for one topic, plagiarism is strictly PROHIBITED. Besides, you should NOT use the examples presented in lecture notes!