An excellent automobile control arm needs the following key conditions:

1. Strength and durability: The control arm needs to be made of high-strength materials, such as aluminum alloy or steel, to ensure that it has sufficient strength and durability, can withstand various forces and vibrations when the vehicle is running, and maintain stability and safety.

2. Accurate geometry: The control arm needs to have accurate geometry and size to ensure the accurate cooperation and connection with other suspension components and ensure the normal operation of the vehicle suspension system.

3. Excellent suspension performance: The design of the control arm needs to consider the working principle of the suspension system and can provide good suspension performance, including suspension stiffness, shock absorption effect and handling stability.

4. Good anti-corrosion performance: The control arm needs to be made of anti-corrosion treatment or anti-corrosion materials, which can resist corrosive substances and harsh environmental conditions on the road surface and prolong the service life of the control arm.

5. Good shock absorption effect: The control arm needs to have good shock absorption effect, which can reduce the bumps and vibrations when the vehicle is driving and improve the driving comfort and stability.

6. Good handling performance: The design of the control arm needs to consider the handling performance of the vehicle, which can provide good handling response and stability and improve driving safety and driving pleasure.

To sum up, an excellent automobile control arm needs to have key conditions such as strength and durability, accurate geometry, excellent suspension performance, good anti-corrosion performance, good shock absorption effect and handling performance to ensure the normal operation and driving safety of the vehicle suspension system.